Clutching means for weaving looms



May 26, 1959 J. PICANOL 2,388,044

CLUTCHING MEANS FOR WEAVING LOOMS File d Nov. 1, 1956 4 Sheets-Sheet 1 mm, INVl-WTO/P ATTORNEY.

4 Sheets-Sheet 2 May 26, 1959 J. PICANOL CLUTCHING MEANS FOR WEAVING LOOMS Filed Nov. 1,, 1956 E M W U F 9 H U 4 I 4 7 2 H 4/ PI Z J Y Z a. PLccLno L, wrz/vrm May 26, 1959 J. PICANOL 2,888,044

CLUTCHING MEANS FOR WEAVING LOOMS Filed Nov. 1, 1956 4 Sheets-Sheet 4 a. PLccLnol, llVl fbral? I p59 GILL: L %4 A TTORNEYJ 2,888,044 Patented May 26, 1959 ice CLUTCHING MEANS FOR WEAVING LOOMS Jaime Picanol, Zillebeke-lez-Ypres, Belgium Application November 1, 1956, Serial No. 619,722

Claims priority, application Belgium December 17, 1955 4 Claims. (Cl. 139-1) It is a fact well known to those skilled in the art of weaving, that in high speed weaving looms each start of the loom leaves traces in the fabric. In the course of a thorough study with the aid of oscillographic measurements judiciously made, applicant has been led to the conclusion, that said traces were particularly clearly visible when the loom was started with the cranks of the crank shaft directed upward, whereas hardly any traces were produced, when the loom was started with the cranks in a rearward direction. From measurements of the forces transmitted on the crank shaft during starting from both said charactereistic initial positions, applicant has been able to establish that there are considerable differences between the couples produced in both said cases. These findings have completely modified the insight into the behaviour of the loom during starting. In fact, it has hitherto generally been accepted, that the traces produced during starting were due to the speed being insufficient during the first weft pick. Starting from this view most of the designers have thought to be able to eliminate said traces by using powerful clutches and by the addition of a flywheel to the motor. These measures have appeared insufiiciently effective.

Now it is of the utmost importance to find an adequate solution for this problem, as by suchlike traces the fabric is considerably depreciated. It is also known, at the other hand, that in the case of a broken thread, the loom practically always stops with the cranks upward, so that the initial conditions for the occurrence of the above-mentioned traces are very often fulfilled. It is therefore of great importance to try to eliminate said traces, but this should be achieved without any restrictions to theway in which the loom is to be started, i.e. it should be possible to start the loom from any initial position. The invention relates to improvements enabling to achieve this dual purpose.

The solution revealed by applicant and which has proved to be a very effective solution, is based on the fact that, contrary to the accepted view according to which insuflicient speed is the cause of the said irregularity, it has now been shown, that said trouble is due to excessive forces. These forces produce elastic deformation of various moving parts, particularly of the crank shaft, the reinforcing cross members and other adjacent elements, said deformation being produced within the short time interval between the starting of the loom and the first pick. As a result, the beating home of the weft is affected with a certain lag or lead, and as it is well known, any change in the way in which the weft is beaten home will leave clearly visible traces in the fabric.

The improvement constituting the main object of the invention consists in providing the clutch device with at least one bufier or cushioning element capable of absorbing, in a measure, the excess forces responsible for the occurrence of said elastic deformations. One may also take it, that said cushioning element confers a certain elasticity to the starting process, without decreasing the power transmitted by the clutch, or otherwise, that said cushioning element slightly prolongs the time interval taken by said starting process, all these effects tending to counteract the production of elastic deformations of the moving parts, at least in a measure sufiicient to avoid the occurrence of said traces in the fabric.

The cushioning element is to be understood any part or group of parts, capable of absorbing part of the forces tending to cause elastic deformation of the members taking part in the beating home of the weft, yet permitting an efiicient coupling to be effected very quickly and forcefully. In this respect the device according to the invention differs from a progressive coupling, which would be inadequate in view of the high speed required for the pick. The device according to the invention may otherwise be applied to clutches of the usual construction, inasmuch it may be mounted on the coupling disc itself. Said device operates in this way, that one or more elastic strips or lamellae are crushed i.e. subjected to elastic deformation, between a driving and a driven element, so as to cause the latter, while the coupling is being effected, to oifer a certain measure of elastic resistance to the former, resulting in a slight delay in fully achieving said coupling. Such a cushioning element could of course be introduced into any other part of the coupling mechanism, provided similar results are obtained as explained before,

As stated in the most general terms, the invention thus consists in the introduction, between the elements of the coupling device, of at least one element capable of diminishing the instantaneous forces arising during the starting in order to prevent said forces from causing elastic deformation of certain moving elements, inasmuch said deformation would produce traces in the fabric.

The characteristic features of the invention will be brought out more clearly in the following description of an embodiment, with reference to the accompanying drawings, in which: 7/

Figure 1 is a schematic view of the essential elements of a weaving loom, intended to show the location of the improved clutching device according to the invention;

Figure 2 illustrates somewhat diagrammatically and very succinctly the principle of a clutch of the usual construction;

Figures 3 and 4 illustrate, in a similar way as Figure 2, the improved clutching deviceaccording to the invention, in two characteristic positions;

Figure 5 schematically shows how an oscillogram may be taken of the forces acting in the crank shaft of a weaving loom;

Figure 6 shows an oscillogram taken on the crank shaft of a loom not provided with the device according to the invention;

Figure 7 shows an oscillogram taken on the crank shaft of a loom equipped with the device according to the invention;

Figure 8 is a sectional view, taken along the line VIII- VIII- VIIL-VIII of Figure 9, of a practical embodiment of the device according to the invention;

Figure 9 shows a sectional view according to the line IX--IX of Figure 8.

As schematically indicated in Figure 2, a clutch device for weaving looms of the usual construction substantially comprises the following elements: the electric motor 1 drives, by means of a driving pinion 2, a toothed rim 3 mounted loosely on the spindle 4 of the crank shaft. A friction disc 5 is keyed on said driven spindle 4; facing the annular friction surface of said disc 5 and at a small distance from the latter is disposed a ring-shaped driving element 6 which may be shifted laterally on said spindle; in the space between both said ring-shaped surfaces of the disc 5 and the ring-shaped driving element 6 respectively is disposed, with some clearance at either side, a ring-shaped element '7 secured on the toothed rim 3 by means of bosses or studs 8. The lateral movement of the ring-shaped driving element 6 is controlled by a certain number of push rods 9, each of which is supported in an intermediate point of a rocking lever '16, one end of which is rotatably mounted on the driven disc 5 by means of a pivot 11, whereas the other end is provided with a roller 12 rotating freely on a pivot 13. The several rollers 12 of said rocking levers l ride on a cam 14 of an axially stationar Y slider 25 fitted on the spindle 4 so as to slide on a corresponding portion of said spindle, it acted upon by adequate control means such as eg a lever system (not shown). Thus if the cam element 14 is shifted into its declutching position, i.e. into a position, in which its narrow part underlies the rollers the levers 10 swing inwards around their respective pivots 11 While pulling the push rods 9 out of engagement with the ring-shaped driving element 6. As a result the distance between said ring-shaped element 6 and the corresponding annular portion of the driven disc increases, whereby the ring-shaped element 7 is liberated, In this position, therefore, the crank shaft remains stationary, in spite of said ring-shaped element 7, together with the toothed rim 3, being driven into rotation by the motor, by means of the pinion 2; secured on the motor shaft. If, on the other hand, the cam member 14 is so shifted as to cause the rollers 12 to ascend the portion of said cam member having the larger diameter, all of said levers will rapidly push their push rods 9 into engagement with the driving element 6, causing the ring-shaped elements 6--7-5 to he suddenly and firmly pressed together, whereby the coupling will be effected almost instantaneously and with a jerk. It is this jerky, almost instantaneous coupling, especially if the said crank shaft is pointing upward, to which the occurrence of traces in the fabric must be ascribed, as explained hereinbefore.

It is the purpose of the invention to introduce into a coupling device of this kind, between at least one driving and one driven element, a yielding link or junction element of such a nature, that at the start the clutching operation is affected by some very slight delay, and yet the friction elements are not prevented from being firmly and very quickly pressed together. This brief intervention of an elastic element during starting may pient excessive forces from being transmitted to certain driven elements and consequently may avoid elastic deformations which would cause imperfections such as have hitherto been found in the fabric For simplification the diagrammatical representation of a. clutching device of usual construction is again used in Figures 3 and 4-, however with introduction of the improvement according to the invention. This improvement consists in that between the driving elem-eat 6 and the push rods 9 cooperating therewith, is interposed at 1-" ct one resilient element such as 15. This resilient element acts so as to introduce, between the instant the push rods 9 come into operation and the instant the ring-shaped elements 6-75 are firmly pressed together, a brief interval during which the final accomplishment of the cou pling is delayed, and also to achieve, in a measure, an elastic yield capable of absorbing the excess forces u would otherwise act upon crank shaft so as to pro duce marks such as have been found in the fabric. elastic elements 25 are so designed as to limit their intervention to an extremely short time interval, said intervention not being capable of preventing the accomplish ment, subject to a short delay, of a powerful compression between the annular elements 6 75, practically in the same conditions prevail in the usual clutches.

It must be realised, that the device in view is neither a progressive coupling, nor an elastic coupling, but an clastic delay device.

With such a device perfectly surprising results have been obtained, as may appear in particular from the oscillograms, which have been taken in a manner as has been diagrammatically indicated in Figure 5, and which reveal considerable differences according to whether they are related to a loom equipped with a clutch of the usual construction, such as the oscillogram shown in Figure 6, or to a loom equipped with a clutch according to the invention, such as the oscillogram shown in Figure 7. Particularly, in the diagram shown in Figure 6 the starting phase is recognizable by the peaks A which reveal the presence of excessive forces, such as will inevitably cause the occurrence of marks in the fabric. It will also be observed from inspection of the curve shown in Figure 7, this this troubled zone has totally disappeared in this case.

As an example a detailed description of an embodiment will hereinafter be given, with reference to Figures 8 and 9. In this embodiment we have again the motor it with the driving pinion 2 secured on the motor shaft and meshing with the toothed rim 3, the latter rotating freely on the hub of a toothed gear 17, which is part of the driving mechanism of the loom. The driven disc 5 is fixedly mounted on said hub 16 of the gear 17 by means of bolts 18. Said disc 5 is preferably faced with friction material 19. The driving ring 6 has a facing 2% which may be similar to the above mentioned facing 1 On the rear side of the driving ring 6 are mounted a number of freely supported resilient strips 15, three in the case represented. Each of said strips may e.g. be fixed on said driving ring, by means of bolts 22-23, while separated from said ring by a spacing element 21. Between the facings 19-20 is disposed the ring-shaped element 7 fixedly secured on the toothed rim 3 by means of bosses 8 and adequate fixing elements such as bolts, rivets, pins or the like 24. Opposite the free end of each of the resilient strips 15 is disposed a push rod mounted on a lever ill rocking about a pivot and provided, at its free end, with a roller 12 hearing on the cam surface 14. Said cam surface is fixed on a slider 25, which may be controlled by a rocking lever 26 pivoting at an intermediate point of its length on a stud 27, the free end of said rocking lever being controlled by means of rod 28 and other operating elements such as are normally used for the coupling in weaving looms. Said slider 25 is mounted on the end of the crank shaft so as to freely slide, with gentle friction, on said shaft.

In exactly the same way as has been explained in general terms with reference to the Figures 3 and 4, the ring-shaped elements 67-5 are firmly pressed together by the action of the pressure exerted by the push rods 9 on the elastic strips 15, but this happens in such a way that during the first instants of the operation, part of the forces or part of the movement, is absorbed by the elastic deformation of said strips 15, whereupon the latter, after being so tensioned, constitute links between said push rods 9 and the ring 6 of suficient rigidity to ensure an equally powerful clutching action as is obtained with the usual clutches, but only after a very short delay caused by the intervention of said resilient strips I5.

As already mentioned before, this embodiment has only been described as an example, it being understood, that the resilient delay element as well as the driving and driven elements and the control organs may be realised in any appropriate shape and dimensions, within the scope and spirit of the present invention as defined in the subjoined claims.

What I claim is:

1. In a weaving loom having a driving mechanism coupled with the moving parts of said loom and a source of motive power, improved clutching means for coupling and uncoupling said driving mechanism with and from, respectively, said source of motive power, said clutching means comprising two driven elements coupled with said driving mechanism, one driving element permanently coupled with said source of motive power and disposed between both said driven elements, operating means for closely associating said driven elements with said driving element so as to ensure the transmission of driving power from said source of motive power to said driving mechanism, and for dissociating said driven elements from said driving element, respectively, and elastic means interposed between said operating means and one of said driven elements, and adapted to intervene in the action of associating said driven elements with said driving element during a short time interval to delay said associating action while permitting said association to take place at the end of said very short time interval, and pressure elements adapted to push said driven elements into intimate engagement with said driving element, said elastic means consisting of resilient strips freely supported on said one driven element, the free ends of said resilient strips cooperating with said pressure elements.

2. In a weaving loom having a driving mechanism coupled with the moving parts of said loom and a source of motive power, improved clutching means for coupling and uncoupling said driving mechanism with and from, respectively, said source of motive power, said clutching means comprising two driven elements coupled with said driving mechanism, one driving element permanently coupled with said source of motive power and disposed between both said driven elements, operating means for closely associating said driven elements with said driving element so as to ensure the transmission of driving power from said source of motive power to said driving mechanism, and for dissociating said driven elements from said driving element, respectively, and elastic means interposed between said operating means and one of said driven elements, and adapted to intervene in the action of associating said driven elements with said driving element during a short time interval to delay said associating action while permitting said association to take place at the end of said very short time interval, a cam element, rocking levers pivoted on the second one of said driven elements, the free end of each of said rocking levers bearing on the surface of said cam element, each of said rocking levers having a push roller mounted thereon, said push rollers being adapted to push said driven elements into intimate engagement with said driving element, said elastic means consisting of resilient strips freely supported on said one driven element, the free ends of said resilient strips being disposed for operative engagement with said push roller.

3. In a weaving loom having a crank shaft coupled with the moving parts of said loom and a source of motive power, improved clutching means for coupling and uncoupling said crank shaft with and from, respectively, said source of motive power, said clutching means comprising a driven disc having a hub keyed on said crank shaft, a ring-shaped driven element mounted on said hub so as to slide thereon, a ring-shaped driving element permanently coupled with said source of motive power and disposed between said driven disc and said ring-shaped driven element, operating means for closely associating both said driven elements with said driving element so as to ensure the transmission of driving power from said driving elements to said driven element, and for dissociating said driven elements from said driving element, respectively, said operating means comprising a cam element fitted to slide with gentle friction on said crank shaft, rocking levers pivoted on said hub of said driven disc, rollers rotatably mounted at the free ends of said rocking levers and bearing on the surface of said cam element, each of said rocking levers having a push rod mounted thereon, resilient strips freely supported on the rear face of said ring shaped driven element, the free end of each of said resilient strips being disposed for operative engagement with one of said push rods, and means for shifting said cam element on said crank shaft, the surface of said cam element being adapted to cause said rocking levers to move their respective push rods into, and out of, respectively, operative engagement with said resilient strips, when acted upon by said shifting means.

4. Improved clutching means as claimed in claim 3, in which there are provided three such rocking levers pivoted on said hub of said driven disc, each provided with a push rod mounted thereon, and three such resilient strips freely supported on the rear face of said ring-shaped driven element, each of said strips having its free end disposed for operative engagement with one of said three push rods, said levers being adapted to be acted upon simultaneously and in the same way by said cam element.

References Cited in the file of this patent UNITED STATES PATENTS 833,982 Snyder Oct. 23, 1906 998,808 Steere July 25, 1911 1,883,743 Maybach Oct. 18, 1932 1,915,732 Goldschmidt June 27, 1933 2,370,360 McLean et al. Feb. 27, .1945

FOREIGN PATENTS 502,850 Belgium May 15, 1951 656,096 Germany Ian. 29, 1938 

